How to Choose Lens for DSLR Based on Focal Length and Speed

How to Choose Lens for DSLR Based on Focal Length and Speed ? How you will determine which Lens is not a bad investment but a good to have in your camera bag ? Like many other hobbies, DSLR photography can be very expensive. Soon, as that our passion for photography and our knowledge grows up, we realize that the Lens purchased has some technical boundaries. We also discover that the camera body itself has more advanced features, if we would provide new creative tool like a new lens we possibly can create more great compositions at certain focal length. But the question bounces back – How to Choose Lens for DSLR ? With the same given focal length value; there can be several variations and options.

How to Choose Lens for DSLR : Are You Using a Full-Frame DSLR ?

The right answer to the asked question “How to Choose Lens for DSLR” will be another question. Are you using a Full-frame DSLR or a DSLR with APS-C sensor format and buying or planning to buy gradually 3-4 lenses including your kit lens ? If you read our article on APS-C Format Sensor, you will discover that, usually a Full-Frame DSLR camera has a separate set of Lens which might be used on Film DSLR and possibly will have less crop factor. As your hobby is growing, your number of lenses will gradually increase and may be you will want an upgrade to a Full-Frame DSLR sooner or later. Make the point sure that lenses are compatible with Full-Frame DSLR camera.

We then should browse catalogs of the camera manufacturer’s lens and lens manufactured by third parties in search of the best upgrade for our equipment. But between buying a more advanced camera body and increasing our lens, no doubt, in our opinion the option must be reviewed by yourself. On the other hand, changing a lens with characteristics different from those we already have gives us many more new creative possibilities rather than changing the camera body. In some cases, it may give access to kinds of photos which were us impossible (an example would be macro photography) for us to take before. Now, we are taking that, you have thoughtfully set your mind to change the lens.

How to Choose Lens for DSLR : Theories

The Lens for digital SLR cameras have odd names consisting of multiple acronyms and numbers that describe all the features. Unfortunately, this nomenclature can be very cryptic and indecipherable at the beginning of the hobby. In addition, some acronyms depend on the manufacturer of the lens: different symbols indicate the same characteristics (!). In this article we introduce two basic features to distinguish between the Lenses. The basic variables are :

1. Focal Length
2. Lens Speed i.e. Maximum Aperture
3. Zoom or Fixed Focal Length
4. Special Lens like with Aspherical lens
5. Number and curvature of the diaphragm blades

Basically the list is quite big, we are excluding all the options keeping the first two variables and partially the third option. First, read these recommended articles either now or after first time reading of this webpage, particularly if you have less theoritical and practical experience with Film SLR camera or you are fully new to SLR world.

Recommended Readings :

1. Lens Speed or Maximum Aperture
2. Aperture of a Lens
3. Diaphragm Blades of a Lens
4. Anatomy of a DSLR Lens

Unfortunately the list can be bigger but we have to stop here.

How to Choose Lens for DSLR Based on Focal Length and Speed

Focal length is definitely the most important feature. It tells how a lens can “approximate” the subject. Depending on the focal length, the lenses can be divided into some categories. The objectives in each category are united by introducing alterations compared to human vision and situations of use recommended :

• Wide angle lenses have a focal length less than 50 mm. Allows you to include many objects (or very large objects) in the frame as they have a wider viewing angle than that of the human eye. Typically they are used for landscape photos.
• Standard lenses : they have a focal length of 50 mm. The lens in this category provide vision which is more similar that of the human eye. They are widely used in street photography, because it reinforces the impression of being in the scene. They are used successfully in portraits. Typically, they are extremely versatile.
• Telephoto: Have a focal length from 70 mm and up. They allow a higher magnification compared to human vision and make the longer objects to be framed as if from closer. Focal lengths between 85 mm and 105 mm are about much portraits. Going further up, some possible applications are nature photos and sporting events. Pictures of very distant objects require focal lengths really, really high (400, 500, 600 mm …). For a dragonfly sitting on a leaf physically 20 feet away requires very high focal length (at least 300mm here) lens.

Last important thing to know about the focal length is that, the objectives can cover a range of focal lengths or have a single focal length – zoom and fixed focal length lens. But then why should we buy a fixed focal length lens as priority ? The reasons are numerous. Among the most important fact, the fact that often comes in to practical usage is – the fixed focal length lenses allows to take sharper photos, primarily because they are more simple by design. Furthermore, we can not zoom our natural eye. Our vision is kind like that of a Fixed focal length lens / prime lens. Its an odd or noble feature that our lens of our eye itself can change in focal length. As the optics is easier with a given focal length, we actually get a blurred effect (which we ignore) for objects at other than ‘not looking’ distance. The effects are closer in prime lens with aspherical lens design.

Very wide opening or aperture allows to obtain a pleasant blur effect, as well as to let more light to enter through the lens. Therefore, the maximum opening allowed by a lens is a fundamental parameter to understand and evaluate while buying a lens. It is important to know when considering a zoom lens, which can have two values ??of maximum opening. This can be a disadvantage, as it forces to take into account that, by increasing the magnification, it decreases the opening and this may alter the photograph that you want to do in a manner which is not desired (for example, changing the depth of field).